Solution or bath for use in electrically preparing stencil-plates, die-plates, and the like



G. E. WERTHEIMER.

SOLUTION 0R BATH FOR USE lN ELECTRICALLY PREPARING STENCIL PLATES, DIE

PLATES, AND THE LIKE.

APPLICATION FILED 05024. 1911.

1,376,366. Patented Apr. 26, 1921.

v UNITED STATES PATENT OFFICE.

GOTTHOLD E. WERTHEIMER, OF NEW YORK, N. Y.

SOLUTION OR BATH FOR USE IN ELECTRICALLY PREPARING STENCIL-PLATES, DIE- .PLATES, AND THE LIKE.

Specification of Letters Patent.

Patented Apr. 26, 1921.

Application filed December 24, 1917. Serial No. 208,559.

To all whom it may oncern:

Be it known that I, GoT'rHoLD EPHRAIM \VERTHEIMER. a subject of the Emperor of Austria, and a declarant of the United States,

having made my application for first papers in March, 1917, residing at 558 \Vest 36th street, New York, in the county of New York and State of New York,have invented certain new and useful Improved Solutions or Baths for Use in Electrically Preparing Stencil- Plates. Die-Plates, and the like, of which the following is a specification.

This invention relates to a composition of matter adapted to be used as the solution or bath in connection with a process of preparing metallic stencil plates or die plates or blocks or like articles, involving the erosion or eating away of certain parts of such plates by the use of electric current in conjunction with said solution or bath.

The object of the present invention is to provide a solution or bath which will enable said process to be expeditiously applied to annealed or hardened metals, such as steel, whereby stencil or die plates or blocks formed of such annealed or hardened metals may be rapidly produced at a low cost and with a minimum of labor.

Another object of the invention is to provide a solution or bath by the use of which the metal from the plate or block ma be rapidly removed while producing a uni orm and smooth surface on the remaining portion of the plate or block.

The improved solution or bath according to the present invention comprises a mixture of sulfuric and nitric acids, ammonium chlorid and water. These ingredients are preferably employed in the proportions of eighty parts of sulfuric acid, twenty parts of nitric acid, two hundred parts of ammonium chlorid, and seven hundred parts of water.

In preparing the solution, granulated ammonium chlorid is firstly dissolved in water, at approximately the boiling point in substantially the proportion of one pound of ammonium chlorid to one gallon of water. By this means a saturated solution of ammonium chlorid is obtained. The other ingredients are mixed together in substantially the proportions stated, and the solution of ammonium chlorid prepared as described, in substantially the proportion given above is added thereto, the entire mixture being thoroughly stirred to secure an intimate admixture of the various ingredients.

The resulting solution is then preferably heated to a temperature of approximately eighty-three degrees Fahrenheit, and maintamedat about that temperature during the operation of the process, by any suitable electrical or other means. The solution may, of course, be used cold, but it is found that the best results are obtained when the same is kept at the temperature mentioned while the process is in operation.

The accompanying drawing diagrammatically indicates the manner in which the solution may be used in the treatment of a metallic plate or block from which a stencil plate or die plate is to be prepared.

The metallic plate or block 1 to be operated on is immersed in the solution or bath 2 contained in a suitable tank or receptacle 3 and an electric current of suitable strength is passed through the plate or block serving as an anode and through the solution to a suit able cathode 4, and it is found that those parts of the plate or block unprotected by a resisting coating of suitable form are very rapidly eroded or cut away. In tests which have been made with this solution heated to the temperature above mentioned and using an electric current of about 6 or 7 volts and about 35 to 40 amperes, it has been found possible to cut into annealed or hardened steel to a depth of three sixty-fourths of an inch in one hour over any desired configuration. The great utility of this solution or bath for the purpose stated will thus be readily recognized.

I have found that the addition to the solution or bath of copper nitrate, or iodin, or acetic acid, or all of them, in small proportions, tends to reduce the erratic action of the solution on the metal and to increase the uniformity and smoothness of the surfaces produced thereon. Preferably these ingredients are added to the solution in the proportions of five parts of copper nitrate, two parts of iodin, and two parts of acetic acid, the number of parts of water being reduced accordingl f The inclilsion of the granulated ammonium chlorid in the solution has been found to considerably reduce the time necessary to cut to a particular depth in, or remove a certain amount of metal from, a metallic plate or block, and in the majority of cases its use will be commercially and practically desirable for this reason. It is to be understood however that the solution composed of the other ingredients above mentioned, without the ammonium chlorid and with an added two hundred parts of Water has been employed, and it has been found that the use of such solution enables die plates or blocks or stencil plates or the like to be produced in a materially shorter time than by the existing methods. WVith such solution it has been found possible to cut to a depth of one millimeter in annealed steel in six hours. This is in itself an important advance on existing methods, and a comparison of this rate of cutting with that above stated when the ammonium chlorid is employed, will serve toindicate the great advantage in the use thereof.

The solution herein described is particularly intended for use in connection with the process described in my companion application Serial No. 208,558, filed December 24th, 1917.

What I claim and desire Letters Patent is 1. A solution for use in the electrolytic treatment of metallic plates or blocks, prepared by mixing together sulfuric acid, nitric acid, ammonium chlorid and water.

2. A solution for use in the electrolytic treatment of metallic plates or blocks, prepared by mixing together the following ingredients in substantially the following proportions, namely, sulfuric acid 80 parts, nitric acid 20 parts, ammonium chlorid in solution 200 parts, and water 700 parts.

3. A solution for use in the electrolytic to secure by treatment of metallic plates or blocks, prepared by mixing together sulfuric acid, nitric acid, ammonium chlorid and water, and a small proportion of iodin.

4;. A solution for use in the electrolytic treatment of metallic plates or blocks, prepared by mixing together the following ingredients in substantially the following pro portions, namely, sulfuric acid 80 parts, nitric acid 20 parts, ammonium chlorid in solution 200 parts, iodin 2 parts and water 698 parts.

5. A solution for use in the electrolytic treatment of metallic plates or blocks, prepared by mixing together sulfuric acid, nitric acid, ammonium chlorid, and water heated to a temperature of approximately 83 Fahrenheit.

6. The method of preparing a solution for use in the electrolytic treatment of metallic plates or blocks which consists in mixing together sulfuric acid, nitric acid and water, dissolving granulated ammonium chlorid in water in proportions to produce a saturated solution, adding the ammonium chlorid solution to the mixture of the other ingredients and thoroughly stirring the entire mixture.

7. The method as claimed in claim 6, wherein the mixture is heated to a temperature of approximately 83 Fahrenheit and is maintained at that temperature during use.

In testimony whereof I afiix my signature in presence of two witnesses.

GOTTHOLD E. WVERTHEIMER.

lVitnesses: I

CHAS. B. CRoMProN, MAY G. LUTTRELL. 

